This invention relates generally to treating of tubular members, including induction heating of same; more particularly it concerns method and apparatus for induction heating of oil well pipe connections as for example in the field and about oil rigs, to facilitate make-up and disconnection of pipe joints.
When making up oil well tubing and casing it is necessary to remove all foreign materials. After cleaning and inspecting the threads and seals for any transit damage, they are lubricated and screwed together. Under normal ambient temperature conditions these processes are easily performed in the field; however, under arctic winter conditions it has been determined that most solvents will not clean the joints properly, that the lubricant will not spread properly and that threaded joints will not make up fully under usually applied torque ranges and methods. In this regard, the viscosity of the cold, thread lubricant prevents the complete make-up of the threads. After the pipe has been put into the well, the increased temperature will thaw the lubricant and expose loose joints and a possible leaker.
Steam heating has been used to clean the piping but this will cause hard ice to form as the steam condenses. Such ice formation on the threaded joint causes similar problems. Heated buildings have sometimes been provided in which the pipe preparations can be made and, also to provide heated areas for the pipe when running the pipe into the well. However, this method is very costly and not fully satisfactory.